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Phosphor-converted white laser diode (WLD) is considered as a promising light source in next-generation high-brightness lighting. However, the WLD suffers from low optical quality in luminous efficacy and color rendering. In this work, we fabricated a high-quality WLD by a blue laser-driven a tricolor phosphor-in-glass (PiG) film-on-sapphire (PIGS). The tricolor PiGS was prepared by sintering a green/yellow/red phosphor glass film on a sapphire substrate. The optical quality of tricolor PiGS-WLDs were optimized by adjusting the phosphor ratio. At the phosphor ratio of 9:6:1, the PiGS-WLD achieves high optical quality with a luminous flux of 362.1 lm, a color rendering index (CRI) of 80.3, and a correlated color temperature (CCT) of 4590 K at a laser power of 2.4 W. The PiGS-WLD has the highest luminous efficacy of 154.5 lm/W at 3.15 W. Furthermore, the PiGS-WLD displays excellent color stability with small CCT and CRI deviation under various laser powers and continuous excitation. The surface temperature of PiGS-WLD is stable at 104 °C due to the high thermal conductivity of sapphire substrate. Therefore, this study provides a stable and high-quality laser-driven white light source for high-brightness lighting and display. [ABSTRACT FROM AUTHOR]

In this article, we propose an all-fiber self-mixing velocimeter based on a DBR fiber laser with adjustable injection intensity for the first time, and theoretically and experimentally explore the behavior of fiber lasers in detecting non-cooperative target under different injection intensities. When the ultra-strong injection level is attained, the linewidth of the DBR fiber laser will be narrowed to about 10 kHz, thus extending the coherence distance of laser tremendously. Simultaneously, the intensity noise can be also significantly suppressed. The non-cooperative target velocity measurement with 40 km single-channel transmission distance has been successfully achieved. This velocimeter is shown to be of great significance in the field of remote sensing with simple and compact configuration, and adjustable dynamical monitoring range. [ABSTRACT FROM AUTHOR]

Monitoring glucose levels is one of the main diagnostic methods for preventing and treating diabetes. Conventionally monitoring of blood glucose through a finger-stick procedure brings pain. It is essential to develop biosensors for low concentration glucose detection in non-invasive samples. In this paper, a tilted fiber grating based localized surface plasmon resonance (LSPR) biosensor for ultrasensitive glucose detection has been demonstrated. The glucose biosensor was fabricated by immobilization of Au nanoparticles (AuNPs) onto an excessively tilted fiber grating (Ex-TFG) and subsequent biofunctionalization by coating polydopamine and concanavalin A onto the AuNPs/Ex-TFG surface. The biosensor has the response regions covering low, middle and high glucose concentrations. The resonance peak indicates a redshift of 0.24 nm, 0.06 nm and 0.48 nm in the concentration ranges of 1.0 nM $- 1.0\,\, \boldsymbol {\mu }\text{M}$ , $1.0\,\, \boldsymbol {\mu }\text{M}- 50.0\,\, \boldsymbol {\mu }\text{M}$ and $50.0\,\, \boldsymbol {\mu }\text{M}-5.0$ mM, respectively. The limit of detection (LOD) of the biosensor in pure phosphate buffered saline is 2.5 nM. The high sensitivity and specific selectivity for D-glucose detection are attributed to strong coupling between the evanescent fields from transverse magnetic (TM) cladding modes of the Ex-TFG and the localized electric fields from LSPR of the AuNPs and their biofunctionalization, and resulting in remarkable enhancement of localized effective refractive index with slightly increased D-glucose concentration. Especially, the glucose biosensor based on the Ex-TFG coupled with the biofunctionalized AuNPs, has been demonstrated to be of practical utility to detect the glucose in artificial urine, which has potential applications in non-invasive glucose monitoring for early diagnosis and better management of diabetes. [ABSTRACT FROM AUTHOR]

By filling the liquid crystal (LC) in the air holes of a photonic crystal fiber (PCF) with 8 mm length, a compact multi-band thermal optical switch is proposed here including two important telecommunication band, i.e., 1265 to 1317 nm and 1508 to 1568 nm. Within the bandwidth, the extinction ratio can be as high as 30 dB. Under the combined action of the bandgap-guiding mechanism and the interference effect, a temperature change of only 1 °C after clearing temperature (Tc) of the LC induces multi-band thermal optical switch of the LC-filled PCF. It is also noted that the transmission spectrum of the LC-filled PCF is quite sensitive to the ambient temperature. The consequent thermal sensitive is 3.9 nm/°C, making it a very good candidate for monitoring the temperature herein. [ABSTRACT FROM AUTHOR]